If you want to think new thoughts, try this: Take something you think is true, and then assume it's false. This is like having a mental teleporter, because it has the neat consequence of transporting you to a point in idea space that you're by definition not going to get to otherwise.

To give it a try, think of a list of things you think are true. They can be anything really, from philosophical beliefs ("people have free will") to policy positions ("the voting age should be at least 18") to personal opinions ("Jane did that because she's jealous of me"). It can take a bit of time to get the hang of this, so stick with it and try to generate a long list. It might help to start with basic facts ("the earth revolves around the sun") just to get yourself going.

Once you've got a list of at least a dozen, choose one of them. If none jump out, choose either the one you're most or least sure of and assume it's false.

What follows? Start with the obvious things ("I don't have control over my life," "there are huge numbers of people in our country that are wrongly disenfranchised," "Jane did that thing for some other reason") and then dive deeper and think of the less obvious logical consequences.

That's where the real value is -- the things two hops away from your initial assumption. Those are the thought-provoking ones, because you can't easily see them from where you're used to thinking.